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Thursday, October 1, 2015

Audino - Arduino MP3-Player

There are several obstacles when creating a MP3 player. Especially if it is a special MP3 player like the Hörbert. There are some other pages that address recreating the Hörbert (here, and here), but there are still missing some information. So let's get started with the first challenge: the components.

With the example sketch "player_simple" the MP3 Shield can be tested. Care must be takenthat the"shield-example object"is created instead of the"breakout-example object".

The output of the Serial Monitor shows the success.

3. Buttons and dot matrix/strip grid board

I want to use just one analog pin to recognize which button is pressed. Therefore several resistors are needed. At the push of a button, a parallel circuit emerges, several resistors are skipped and a voltage change occurs. The voltage change can be recognized at the analog pin, the value indicates the button.

The voltage values for the 11 buttons are shown here:

According to this table the wire layout is created. The wires are connected with the Arduino board/MP3 shield. Red with the 5V pin to supply the buttons with power, black with GND pin, and white with an analog pin to get the signal of the buttons.

Buttons and resistors will be soldered at the back.

Some wires can be seen at the front.

The arduino board is screwed onto the dot matrix/strip grid board, also the battery holder.

Not only the buttons need a connection to the 5V pin, also the potentiometer needs to be supplied with power. Therefore another wire will be used to tap the 5V power supply.

4. Connecting the other components

The potentiometer has 3 pins. On each pin wires with male connectors are soldered. The left wire (red) is connected to the soldered 5V power supply wire. The middle wire (yellow) is connected to analog pin of the arduino board / mp3 shield. The right wire (black) is connected to a GND pin of the arduino board / mp3 shield.

The battery holder is connected to the arduino power jack. The power supply line is cut through to connect the switch button.

Two wires are soldered on the speaker. Then the wires are connected to the MP3 shield.

And so far that is the result

5. Housing

The hardware needs now some housing. Potentiometer and switch button are mounted on the top of the housing. The dot matrix/strip grid board and the speaker with the protective grille are mounted on the front. Through the back the screwed components can be accessed.

6. Sketch

The sketch let the potentiometer act as volume control, recognizes the buttons and goes to the start, next, previous, first or last mp3 track or fast-forwards the mp3 track. The current mp3 track will also be remembered, so next time the Audino is switched on the remembered track will be played again.

7. PC-Software

The Audino is now ready for use. On the micro SD card the folders "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" must be created. Several mp3 tracks can be added to the folders 1 - 9. The mp3 tracks in each folder must be numbered consecutively (1.mp3, 2.mp3 ...). Hence just one channel is used the mp3 tracks should be in mono.

I created a PC-Software to simplify the copy process. The playlists can be planed and created.